Clinkering, processing and characterisation of alite-belite-ye’elimite eco-cements: From basic to applied science
- Autores: Jesús David Zea García
- Directores de la Tesis: Mª Isabel Santacruz Cruz (dir. tes.), Maria de los Ángeles Gómez de la Torre (codir. tes.)
- Lectura: En la Universidad de Málaga ( España ) en 2020
- Idioma: español
- Tribunal Calificador de la Tesis: Aurelio Cabeza Díaz (presid.), Marta Palacios Arévalo (secret.), Nicoletta Marinoni (voc.)
- Programa de doctorado: Programa de Doctorado en Química y Tecnologías Químicas. Materiales y Nanotecnología por la Universidad de Málaga
- Materias:
- Enlaces
- Resumen
An eco-friendly industrial production is essential to protect our environment. The most widely used manufactured material in the world is PC concrete, which is mainly composed by water, aggregates (rocks and sand) and PC. The synthesis process of PC generates greenhouse gas emissions. Because of that, the cement industry is under increasing scrutiny to reduce CO2 emissions, including the energy used in the production of PC. The cement production is a highly energy demanding industrial process. The major challenge in cement production is to reduce the high input of raw material and fuel in clinker production. These reductions can be addressed by adopting a suitable processing method. This can be reduced by using blended cement with highly efficient clinker cooler, dryer, separators, calciner, pre-calciner and waste heat recovery system.
This PhD thesis is focused in the production and characterisation of eco-cements with alite, belite and ye’elimite phases. It has been gathered in two blocks: on the one hand, a deep characterisation of the hydration of the main phases of this type of cements, alite and ye’elimite pure phases, has been performed to understand them. The corresponding hydration products (which contain nanocrystalline and crystalline phases) have been characterized through PDF methodology. On the other hand, the synthesis, hydration understanding, processing and the corresponding characterisation of ABY cements and mortars have been performed. Here, both standard (ABY, composed by beta-belite) and doped (dABY, with alpha-belite) cements/mortars have been prepared and characterised.
Summarising, this first part of the PhD has enabled us to establish a multi-r range methodology for the analysis by PDF of mixtures of crystalline/nanocrystalline/amorphous components. Moreover, C-S-H gel has been characterised and described as nanocrystalline defective tobermorite, monolayers of portlandite and water pore, independently of the polymorphism of alite, particle size, water to solid mass ratio or temperature. Finally, aluminium hydroxide gel obtained from the hydration of ye’elimite has also been described. The type and amount of the sulphate source seems not to have any influence on the nanocrystalline nature of this phase.
The results obtained from this second part of the research work have allowed fulfilling the specific objectives of synthesizing, “scaling-up” and hydration understanding for both ABY and dABY cements, which mortars show similar performances than PC but ~17% less CO2 emissions. In addition, the goal of enhancing the performances of these types of materials by doping with boron has been achieved as the ratio CO2/MPa has decreased from 0.018 to 0.011 at 28 days when compared to PC (w/c=0.50).
